import { describe, test, expect } from 'bun:test';
import {
	cdata,
	escapeXml,
	feedFingerprint,
	formatRFC822,
	formatReadableDate,
	formatVerseText,
	latestModification,
	todayInTimeZone
} from '$lib/server/rss';

describe('RSS date formatting', () => {
	test('formatReadableDate uses the calendar day, independent of server TZ', () => {
		expect(formatReadableDate('2026-09-18')).toBe('September 18, 2026');
		expect(formatReadableDate('2026-01-01')).toBe('January 1, 2026');
	});

	test('formatRFC822 emits a valid GMT timestamp', () => {
		expect(formatRFC822('2026-01-15')).toBe('Thu, 15 Jan 2026 05:00:00 GMT');
		expect(formatRFC822('2026-09-18')).toBe('Fri, 18 Sep 2026 04:00:00 GMT');
	});

	test('formatRFC822 handles daylight saving (EST -05:00 vs EDT -04:00)', () => {
		// Winter: midnight New York is 05:00 UTC.
		expect(formatRFC822('2026-01-15')).toContain('05:00:00 GMT');
		// Summer: midnight New York is 04:00 UTC.
		expect(formatRFC822('2026-07-15')).toContain('04:00:00 GMT');
		// Never a bare, ambiguous abbreviation like EST/EDT.
		expect(formatRFC822('2026-07-15')).not.toMatch(/\bE[SD]T\b/);
	});

	test('todayInTimeZone respects the reference timezone', () => {
		// 02:00 UTC on the 23rd is still the evening of the 22nd in New York.
		expect(
			todayInTimeZone('America/New_York', new Date('2026-09-23T02:00:00Z'))
		).toBe('2026-09-22');
		// 04:00 UTC on the 23rd is midnight in New York.
		expect(
			todayInTimeZone('America/New_York', new Date('2026-09-23T04:00:00Z'))
		).toBe('2026-09-23');
	});
});

describe('RSS content fingerprint', () => {
	const row = { date: '2026-09-18', reference: 'Leviticus 19:9-11', verseText: 'a' };

	test('is stable for identical content', () => {
		expect(feedFingerprint([row])).toBe(feedFingerprint([{ ...row }]));
	});

	test('changes when verse text changes', () => {
		expect(feedFingerprint([row])).not.toBe(feedFingerprint([{ ...row, verseText: 'b' }]));
	});

	test('changes when the set of days changes', () => {
		expect(feedFingerprint([row])).not.toBe(
			feedFingerprint([row, { ...row, date: '2026-09-17' }])
		);
	});
});

describe('latestModification', () => {
	const fallback = new Date('2026-09-18T00:00:00Z');

	test('returns the newest createdAt', () => {
		const older = new Date('2026-09-16T10:00:00Z');
		const newer = new Date('2026-09-17T10:00:00Z');
		expect(
			latestModification([{ createdAt: older }, { createdAt: newer }], fallback)
		).toEqual(newer);
	});

	test('falls back when rows have no timestamp', () => {
		expect(latestModification([{ createdAt: null }], fallback)).toEqual(fallback);
		expect(latestModification([], fallback)).toEqual(fallback);
	});
});

describe('XML serialization helpers', () => {
	test('escapeXml escapes all predefined entities', () => {
		expect(escapeXml(`<a href="x">&'</a>`)).toBe(
			'&lt;a href=&quot;x&quot;&gt;&amp;&apos;&lt;/a&gt;'
		);
	});

	test('cdata splits embedded CDATA terminators', () => {
		expect(cdata('a]]>b')).toBe('<![CDATA[a]]]]><![CDATA[>b]]>');
	});

	test('formatVerseText capitalizes and replaces trailing punctuation', () => {
		expect(formatVerseText('for God so loved the world,')).toBe('For God so loved the world...');
	});
});